“Itch” is an unpleasant condition on the skin surface, generally defined as a sensation that causes or leads a subject or patient to scratch the area or location on the subject where the sensation is perceived. Chronic itch is a common problem associated with skin disease, systemic disease, metabolic disorders, and other conditions. See generally T. Liu and R.-R. Ji, Neurosci. Bull. 28: 145-154 (2012), Numerous different treatments have been suggested. See, e.g., J. Speight, PCT Patent App. WO 97/35573 (Oct. 2, 1997); T. Jung and J. Meingassner, PCT Patent App. WO 2008/129000; and E. Lerner and V. Reddy, US Patent App. US 2011/0184016 (Jul. 28, 2011). Because the consequences of scratching can exacerbate the sensation of itch, and lead to other problems such as infection, there remains a need for new methods and compositions for the treatment of pruritus.